1. Field of the Invention
The present invention is used in a Graphics Display Terminal and relates to a feature whereby certain segments displayed on the CRT can be classified and assigned to or removed from one or more classes, and certain ones of these segments, which satisfy an input condition, can be modified or highlighted on the display.
2. Description of the Prior Art
Graphics Display Terminals display images which comprise a plurality of "segments". For example, when displaying a street map which includes a plurality of restaurants, the restaurants may be considered to be "segments". A graphics display terminal used in an air traffic control environment may display the local air traffic, where each air vehicle being displayed may be considered a "segment". In a military environment, air and sea traffic may be displayed on such a terminal, each sea and air vehicle being a "segment".
The prior art graphics display terminals identified each segment by a segment number and classified it by assigning to it a class number. The class number would, for example, classify the segment as being a ship or an airplane. However, these prior art terminals could not selectively assign these segments to or remove these segments from more than one class simultaneously using a single input command instruction. In addition, these prior art terminals could not selectively recall from memory and modify the attributes or highlight certain ones of these segments which satisfy a particular input condition. Furthermore, these prior art terminals could not perform a wide range of "generic" segment operations on a set of segments determined by an arbitrary Boolean sum-of-products of class membership by referring to such a set through a reserved segment number.